Friday, 24 June 2016

You know that situation where you're walking across a train station concourse or a park and there's another person walking on a different trajectory that means if you both hold your course and speed, you're going to collide? Are you the kind of person who assumes the other guy will give way, or are you the polite one who slows down and lets the other person cross your path?

A new study in the Journal of Experimental Psychology: Human Perception and Performance recreated this scenario by pairing up 20 participants – a mix of young men and women – and having one person in each pair walk diagonally from one corner of the room to the other, while the other person walked the other diagonal (see schematic below). On each of many trials, both participants in each pair began walking on a starting signal and they were asked to make sure they didn't collide, all without communication with each other. The participants also filled out personality questionnaires and the researchers recorded their heights, weight and age.

The participants tended to show a consistent pattern of behaviour across trials: roughly a quarter were more inclined to give way to avoid colliding; a quarter usually crossed the potential interception point first, making the other person give way; while the others showed a mixture of behaviours. But crucially, neither personality traits, gender, age, height or weight were related to what kind of collision avoidance strategy the participants tended to use. So it seems some of us are dominant in this situation, some more timid, others ambivalent, but the kind of pedestrian we are is not related to major traits such as extraversion nor to our physical size.

Alexander Knorr and his team performed a second study in a bigger room with more participants and this showed that the decision about who will give way tends to be made very early. The more dominant person actually tends to make a slight adjustment to heading and speed first, but this isn't sufficient to avoid a collision. The second person who ultimately gives way seems to detect these early signals, then waits and makes their own adjustments thus avoiding the collision.

What this research doesn't address, sadly, is that other pedestrian problem of when you're heading straight towards another person, and you both dodge out of each other's way in the same direction, then the other, so you end up virtually colliding and uttering embarrassed apologies – or is that just a British thing?